Chronic pain is a costly syndrome that influences every aspect of a patient's life. Significant interference with sleep, employment, social functioning, and daily activities is common. Chronic pain patients frequently report depression, anxiety, irritability, sexual dysfunction, and decreased energy. Family roles are altered, and worries abound about financial limitations and future consequences of a restricted lifestyle. Epidemiological studies have independently documented that chronic pain is an immense international problem. Chronic pain symptoms afflict one third of the American population (more than 80 million people). Chronic pain accounts for 21% of emergency room visits and 25% of annual missed work days. When direct and indirect costs are considered, chronic pain imposes a greater economic burden than any other disease, with annual estimates up to $100 billion.